The traditional channel of monetary policy is the interest rate channel. This
is basically associated with changes in real money supply. Contractionary
monetary policy either through open-market sales of securities or an increase
in the policy rate raises short-term nominal interest rates. with some degree
of price stickiness, the rise in the nominal interest rate correspondingly
increases the real interest rate, which alters the consumption and investment
decisions of economic agents, leading to a reduction in aggregate demand.
Empirical studies have found, however, that the macroeconomic impact of a
policy-induced rise in interest rates is much larger than the implied interest
elasticities of consumption and investment, suggesting that there are other
broader mechanisms at work
Another channel that is particularly relevant to small, open economies is the
exchange rate channel. This channel has become more important given the
greater integration of commodities, services and financial markets alongside
greater exchange rate flexibility. The chain of transmission operates through
the uncovered interest rate parity condition, wherein an increase in domestic
interest rates–ceteris paribus–renders holdings of domestic assets more
attractive relative to foreign currency-denominated assets. This encourages
foreign exchange inflows and therefore leads to an increase in the value of the
domestic currency relative to other currencies, hence, an appreciation. The
higher value of the domestic currency makes domestic goods more expensive
than foreign goods, causing a reduction in net exports, and therefore, in
aggregate output.
The credit channel assigns an active role to the supply of loans in the monetary
policy transmission process. It captures the bank lending and balance sheet
effects (broad credit channel) of a policy-induced change in short-term nominal
interest rates. In this channel, the traditional cost-of-capital channel (i.e.,
interest rate channel) is amplified and propagated by how changes in policy
rates affect the availability and cost of credit. Research on the credit channel
picked up considerably starting the 1990s when concerns about credit crunch
were widespread.
The bank lending channel is premised on the fact that banks play a special
and central role in the financial system because they are well suited to solve
asymmetric information problems in credit markets. Some borrowers (including
small- and medium-sized enterprises and households) are very dependent on
bank financing and can only access credit markets through bank borrowings.
The broad credit channel focuses on all forms of external finance that firms
can tap but at a cost premium. This external finance premium compensates
lenders for the monitoring and evaluation of loans and is affected by the stance
of monetary policy. Monetary tightening raises the external finance premium
of all funds. This affects a borrower’s balance sheet in at least two ways. one,
higher interest rates raise interest expense, reducing the borrower’s net cash
flow and weakening its financing position.Two, higher interest rates shrink
the value of the borrower’s collateral since these are typically associated with
declining asset prices. In both cases, the decline in the borrower’s net worth
leads to a fall in investment and aggregate demand.
Another transmission channel is the asset price channel. For existing
bondholders, a higher interest rate means a lower value of existing assets.
This implies lower wealth holdings, which discourage current consumption
and investment, and therefore dampen aggregate demand. Apart from the
wealth effect, changes in asset prices also affect aggregate demand through
the valuation of equities (or the Tobin’s q theory of investment). Tobin defines
q as the ratio of the market value of firms to the replacement cost of capital.
If q is high, the market price of firms is high relative to the replacement cost
of capital. If new plant equipment is cheap relative to the market value of
business firms, investment spending will rise. By contrast, with contractionary
monetary policy, interest rates rise, bonds become more attractive than
equities causing the price of equities to drop. This leads to a lower q and
therefore, lower investment spending.
Lastly, the expectations channel has a considerable impact on the significance
of the other channels of transmission. To the extent that wage and price
expectations are forward-looking, expectations can speed up the adjustment
of demand to a change in central bank policy, thus affecting the transmission
lag to inflation.